Ex vivo HR-MAS MRS of human meningiomas: A comparison with in vivo H-1 MR spectra

We report on the magnetic resonance spectroscopy (MRS) characterisation of different human meningiomas. Three histological subtypes of meningiomas (meningothelial, fibrous and oncocytic) were analysed both through in vivo and ex vivo MRS experiments. The ex vivo high-resolution magic angle spinning (HR-MAS) investigations, permitting an accurate description of the metabolic profile, are very helpful for the assignment of the resonances in vivo of human meningiomas and for the validation of the quantification procedure of in vivo MR spectra. By using one- and two-dimensional experiments, we were able to identify several metabolites in different histological subtypes of meningiomas. Our spectroscopic data confirmed the presence of the typical metabolites of these benign neoplasms and, at the same time, that meningomas with different morphological characteristics have different metabolic profiles, particularly regarding macromolecules and lipids. The ex vivo spectra allowed a better understanding and interpretation of the in vivo MR spectra, showing that the HR-MAS MRS technique could be a complementary method to strongly support the in vivo MR spectroscopy and increase its clinical potentiality.